There are known systems for emergency repair of punctured tires, including those in which a sealant is injected through an air valve on a tire after the valve core is removed, the valve core is installed after injection, and high-pressure air is then injected until the tire is pumped up to a sufficient pressure for driving (hereinafter referred to also as “discrete type systems”); and those in which a pressure-proof container containing a sealant, and a high pressure-air source such as a compressor are used to inject the sealant into a tire through the air valve and subsequently continuously inject high-pressure air until the tire is pumped up to a sufficient pressure for driving (hereinafter referred to also as “integrated type systems”). Among such puncture sealants, those which contain natural rubber latex in combination with a resin adhesive and an antifreezing agent as disclosed in Patent Literature documents 1 to 4 have been proposed.
Since puncture sealants are used in a wide range of temperatures, they need to maintain injection properties over a range from low to high temperatures. In particular, they need to avoid an increase in viscosity even at low temperatures. However, the viscosity of puncture sealants usually greatly increases at low temperatures, so that such puncture sealants are difficult to inject or they take a long time to inject. Thus, there is a need for methods of suppressing an increase in low-temperature viscosity. Meanwhile, in view of preventing valve clogging due to an increase in viscosity at high temperatures, the mere combination of latex, a resin emulsion, and an antifreezing agent is insufficient because such a puncture sealant, when used at high temperatures, may coagulate in the air valve, making it impossible to increase the pressure to a predetermined level.